r - Plot points with 3 different colors -

i have following 2 columns part of dataframe , function below:

x 705.7553 789.2789 689.7431 559.8025 629.9365 564.9095  y -0.0596123270783229  0.644158691971081 -0.433854284204926 -0.365746109442603  0.566685929975495  0.398462720589891  

function:

plotm<- function( all.res, m, u ) {   plot(data$x, data$y,        log="x", pch=20, cex=0.7,        col = ifelse( data$y < m, "red", "black" ),         xlab = "y", ylab = expression(log[2]~fold~change)) } 

function call:

plotm(data, .05)  # plots graph red points when  data$y < m , black when data$y > m 

but i'm interested in following:

plotm(data, 0.05, 0.1 )  #  plot graph red points when data$y < m, green when data$y > u, , rest colored black 

can please? thanks

we first generate toy data:

set.seed(1) x <- rnorm(100) y <- rnorm(100) 

you can like:

m <- c(-inf, -0.5, 0.5, inf)  # specify cut points, here -0.5 , 0.5 cols <- cut(y, breaks = m) plot(x, y, col = cols)   

we here use fact cut returns factor, , use numeric values of levels colors. write like:

cols <- as.character(cut(y, breaks = m, labels = c("black", "red", "green"))) 

to construct colours.

alternatively, can use nest ifelse. i.e.

plot(x, y, col = ifelse(y < -0.5, "red", ifelse(y > 0.5, "green", "black")))